Year	Number
1960	8339
1961	8348
1962	8268
1963	8184
1964	8095
1965	8001
1966	7896
1967	7781
1968	7652
1969	7508
1970	7339
1971	6975
1972	6473
1973	6015
1974	5593
1975	5208
1976	4847
1977	4512
1978	4198
1979	3905
1980	3633
1981	3345
1982	2852
1983	2439
1984	2091
1985	1792
1986	1539
1987	1322
1988	1132
1989	972
1990	830
1991	707
1992	600
1993	506
1994	424
1995	357
1996	81
1997	0
1998	0
1999	0
2000	0
2001	0
2002	0
2003	0
2004	0
2005	0
2006	0
2007	0
2008	0
2009	0
2010	0
2011	0
2012	0
2013	0
2014	0
2015	0
2016	0
2017	0
2018	0
2019	0
2020	0
2021	0
2022	0
2023	0